Well, only in america is it controversial for me to begin tonight's program by declaring that global warming is really happening. For doubters, 332-straight months of above average temperatures is not proof enough. And even among believers, there's a fight over who to blame, god or man, natural cycles of fossil fuels. The very words climate change were noticeably absent from this past election, but sandy brought them back in a big way and eager to fuel the conversation, two artists convinced they can help skeptics see climate change in ways scientists cannot. If you drive outside of juneau, alaska, past nugget falls and through the bly colored icebe icebergs, you will find mendenhall glacier. Of what's left of it. The ice came out to right about here in 2007. Reporter: Wow. Five years ago, we'd be bumping into the glacier right here. Yeah. Reporter: And if you time your visit just right, you might run into james, nature photogra, geo-morphologis and reformed climate change skeptic. When I first heard about the man-made climate change story, i had a knee jerk reflexive skepticism. Reporter: But the more he learned about ice, the more he worried. The more time he spent the the arctic, the more he saw glaciers disappearing. And the more he thought about his kids. I imagine myself as an old man sitting on a rocking chair and I hear my daughters saying to me, you know, what were you doing when this change was happening? Reporter: And so he launched the extreme ice survey. An effort to capture the changing planet by placing time lapse cameras at the top of the world. And as you can see in the new film "chasing ice," -- look at that. Look at the whole thing. Reporter: That is no easy feat. This knee's had two surgeries on it already. Reporter: Between the bum knee, the god forsaken cold winds and the fragile cameras, the whole thing nearly killed him. The electronics cost me years of my life in terms of anxiety and tension and high blood pressure and just general suffering. Reporter: That's interesting to know, considering I've seen some of your critics online, who say you're in this for the money. Yeah, right. You know what they can do? They can kiss my you know what about ten times. Reporter: But five years later, here is just one small taste of the fruits of his labor. Visual proof of mendenhall's steady retreat. In the winter, will this come back? The retreat sends to slow down in the wintertime. Maybe it stabilizes or creeps forward a tiny little bit. But boy, as soon as the warming season comes back on, it continues to gobble itself backwards. Reporter: The satellite pictures back that up. Since '79, half the arctic sea ice have disappeared. Just this year, 4.5 scare miles melted away. An area the size of the u.S. And mexico combined. Okay, here it comes. Reporter: Meanwhile, back when jim was mounting his first ice cameras, an artist in brooklyn was pushing the kind of machine you use to chalk lines on a ball field. After reading a scary 2001 prediction from nasa that climate change powered storms would wipe out entire neighborhoods, she decided to see which neighborhoods, by marking the high water line around new york city. This would be under water. This would be dry, so, there would be a little dry strip down the center of the road and all of this would be under water. Reporter: Her chalk was gone by the time sandy hit, but the lines were right. And in many places, the damage exceeded her worst fears. And suddenly, that wishy washy conversation changed. Not so much of an "i told you so" as "i'm really sorry this had to happen." The fact it takes something so drastic, despite people in his administration know about it, you know end that it really takes us having a visceral experience to shift even the conversation. Reporter: Right. Much less action. Reporter: America is the last developed nation still arguing over all of this. On one side, those with the faith that humans could never alter the planet so profoundly. Happy to agree are oil and coal companies and a political party strongly opposed to any new environmental regulations. President obama promised to begin to slow the rise of the oceans. And to heal the planet. My promise is to help you and your family. Reporter: On the other side are 99% of climate scientists WITH Ph.Ds AND THE PRESIDENT. I am a firm believer that climate change is real, that it is impacted by human behavior and carbon emissions. Reporter: And happy to agree are most of the insurance coanies that insure insurance companies. Like munich re. The german giant reported last month that north america is getting the worst of it, as weather disasters cost over a trillion dollars in the last 30 years, as storms quintupled. And they're warning kri iing clients to brace for much more as the melting accelerates. 1984, the glacier was down there, 11 miles away. And today, it's back here. Receded 11 miles. The glacier's retreating, but it is thinning at the same time. Like air being let out of a balloon. You can see what's called the trim line. The high water mark of the glacier, in 1984. That vertical change is the height of the empire state building. Reporter: Skeptics will note on the other side of the planet, antarctic ice is expanding to record levels. But that is cold comfort, when scientists explain that north pole ice is melting eight times faster than the south pole ice can grow in the winter, 25 times faster in the summer. And, so, eve, who has traded her chalk machine in for a stroller the last couple of years, has agreed to revive her high water line project in miami, philadelphia and london. And james vows to keep those cameras snapping. At least until the glaciers start growing. And I'd like to be able to say, girls, I was doing everything that I knew how to do with the skills that I had. And that was witness, tell the story and give voice to this landscape. Reporter: Sound the alarm. Sound the alarm. Reporter: Do you think we've reached the tipping point where people are hearing that alert yet or do you think it will take a major disaster before the world will pull together? Well, I'm afraid that it may take, you know, a really serious, unpleasant set of events before the world truly knuckles down and takes this seriously and does everything that we're already capable of doing to mitigate it. But I hope that's not the case. I hope we're smarter than that.

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